Does SIP Date or Frequency Meaningfully Change the Outcome?
People put real thought into which date of the month their monthly investment should go out on. Across the whole record, the best date beat the worst by an amount that rounds to almost nothing — and the question of how often you invest has a more interesting answer.
Updated 2 September 2026
The question
A monthly investment plan — an SIP — takes a fixed amount from your bank on a chosen date and buys units with it. The date is something you pick when you set it up, and a great deal of advice exists about which date is best.
It turns out to be one of the least important decisions in the whole plan. Here is the evidence, and then what actually does matter.
Every date of the month, the same money
Each row below invests the same amount on the same schedule. The only difference is which date of the month the money goes out. When that date falls on a weekend or holiday, the purchase happens on the next working day, which is what a real bank mandate does.
Because some schedules end up making slightly more payments than others, the comparison is what each rupee invested turned into, rather than the final total — otherwise a schedule would look better simply for having put in more money.
| Investing on | Every ₹1 became | Behind the best day by |
|---|---|---|
| Day 1 | 8.891 | 0.00% |
| Day 5 | 8.836 | 0.63% |
| Day 10 | 8.816 | 0.85% |
| Day 15 | 8.867 | 0.28% |
| Day 20 | 8.872 | 0.22% |
| Day 25 | 8.888 | 0.04% |
| Day 28 | 8.859 | 0.37% |
The best date across the whole record was Day 1 and the worst was Day 10. The gap between them is 0.85%.
Two conclusions follow. The first is that a difference that small is noise. It reflects which dates happened to land near which market movements over one particular stretch of history, and there is no reason for it to repeat.
The second matters more. The winning date can only be identified afterwards. Picking today's best-performing date for tomorrow's investments is choosing based on an outcome that has already happened — the same mistake as buying last year's best-performing fund.
How often you invest: read this one carefully
| Paying in | Every ₹1 became |
|---|---|
| Monthly | 8.891 |
| Quarterly | 8.903 |
| Half-yearly | 9.114 |
| Yearly | 9.472 |
Here there is a visible pattern, and it is easy to draw the wrong conclusion from it. Investing less often looks better. But that is mostly not about frequency.
Paying yearly puts the whole year's money in at the start of the year. Paying monthly spreads it across twelve months, so on average each rupee has been invested for about six months less. In a market that rose over this period, money that went in earlier did better. The table is largely measuring time in the market wearing the costume of frequency.
And there is a cost the number does not show. Paying once a year puts an entire year of saving on a single day's price. If that day happens to be an expensive one, you are stuck with it for the whole year.
There is also a practical point no table captures: most households cannot save a year's worth in advance. If your money arrives monthly, investing it monthly is not the worse option — it is the only one, and the alternative is leaving it in a bank account.
What actually decides how much you end up with
Roughly in order of importance:
- How much you invest, and whether that amount grows as your income does.
- How long you keep going, particularly through the stretches when it feels pointless.
- What the money is invested in — the mix of shares, bonds and cash.
- What it costs. A fund's annual charge is deducted every year you hold it.
- Whether you stop. A plan interrupted during a market fall does more damage than every calendar decision on this page put together.
The date does not appear on that list.
Choose the date for practical reasons
Set it for shortly after your salary reliably arrives. That is the entire optimisation.
It reduces the chance of the payment failing for want of funds, it takes the money before it can be spent on something else, and it removes a decision you would otherwise keep revisiting.
Then leave it alone. A plan that runs for twenty years on an unremarkable date beats a well-chosen date that gets cancelled in year three.
What to take away
Pick a date shortly after payday and stop thinking about it. If somebody shows you the historically best date to invest on, ask what that date was according to data ending five years earlier. It will usually be a different one, which is the whole point.
Educational content only. This is not personalised financial, investment or tax advice. Figures quoted are historical or illustrative and are not forecasts. Consult a qualified professional before acting on anything you read here.